1. Field of the Invention
The invention concerns reactive iridoid derivatives of the general formula I ##STR2## wherein R is a hydrogen atom, an alkyl group with 1 to 5 carbon atoms, an acyl group with 2 to 6 C atoms, an unsubstituted aralkyl group with 7 to 12 C atoms, a methanesulfonyl- or toluenesulfonyl group, a benzoyl-, a preferably para-substituted nitrobenzoyl- or chlorobenzoyl group or a tetrahydropyranyl group.
2. Description of the Prior Art
The iridoids are a group of natural substances whose common structural feature consists of the cyclopentanpyran ring system: ##STR3## The iridoids occurring in nature are generally present in the form of glycosides, wherein their sugar is linked with the C.sup.1 -atom of the iridoid. An iridoid glycoside which can be isolated easily from the drug Picrorhiza kurrooa, Royle (Indian Gentian, family Scrophulariaceae) is the Catalpol of formula II ##STR4## which is characterized by the epoxide ring between C.sup.7 and C.sup.8 and is present as 1-.beta.-D-glucopyranoside.
A survey of the iridoid glycosides and their isolation is to be found in the article of O. Sticher and U.Junod-Busch in: Pharm.Acta Helv. 50, pp. 127-144 (1975).
It is the aim of this invention to provide the compounds of general formula I and the simplest possible procedure for their manufacture, thus also providing a new and simple access to reactive iridoid derivatives, in order to open up in this manner new ways of synthesizing pharmacologically effective classes of natural substances, prostanoids in particular.